1. Field
The disclosed technology relates to a substrate printing device and a substrate printing method, and more particularly to a top-down thin film substrate printing device and method.
2. Description of the Related Technology
An organic electroluminescence display device includes organic light emitting diodes (OLEDs), and emits light by energy that is generated when excitons, which are created through combination of electrons and holes within organic light emitting layers of the OLEDs, fall from an excited state to a ground state.
An organic electroluminescence display device could be fabricated on a piece-by-piece basis. However, in order to improve manufacturing productivity and save on cost, multiple display devices are formed on one mother substrate, and then are respectively cut from the substrate to form individual display pieces.
Unlike existing LCD products, OLED displays are fabricated using a thin film process. During layer deposition if particles are present on the processing surface, the impurities can result in illumination defects, such as dark defects, always off pixels, and dark spots. Particularly with respect to a large-size form factor, such as a TV, if particle management is not adequately addresses, the yield rate of the manufacturing line diminishes.
As a result of adopting the printing method used in existing LCD manufacturing processes, such as ink jet, nozzles, and stripe coating, in fabricating organic electroluminescence displays, the number of dark spots in a product having as small as a 4-inch display screen can the range upwards of 2,000, and thus, cost effective manufacturing is not possible.